#include <stdio.h>
#include <Windows.h>
#include <stdlib.h>
#include <time.h>
#include <conio.h>

#define ROW 22 
#define COL 42 
#define KONG 0 
#define WALL 1 
#define FOOD 2 
#define HEAD 3 
#define BODY 4 
#define UP 72 
#define DOWN 80 
#define LEFT 75 
#define RIGHT 77 
#define SPACE 32 
#define ESC 27 

struct Snake{
	int len;
	int x;
	int y; 
}snake;

struct Body{
	int x; 
	int y; 
}body[ROW*COL]; 

int face[ROW][COL]; 

void HideCursor();
void CursorJump(int x, int y);
void InitInterface();
void color(int c);
void ReadGrade();
void WriteGrade();
void InitSnake();
void RandFood();
void JudgeFunc(int x, int y);
void DrawSnake(int flag);
void MoveSnake(int x, int y);
void run(int x, int y);
void Game();

int max, grade; 
int main(){
	max = 0, grade = 0; 
	system("title 贪吃蛇"); 
	system("mode con cols=84 lines=23"); 
	HideCursor(); 
	ReadGrade(); 
	InitInterface();
	InitSnake(); 
	srand((unsigned int)time(NULL)); 
	RandFood(); 
	DrawSnake(1);
	Game(); 
	return 0;
}

void HideCursor(){
	CONSOLE_CURSOR_INFO curInfo; 
	curInfo.dwSize = 1; 
	curInfo.bVisible = FALSE; 
	HANDLE handle = GetStdHandle(STD_OUTPUT_HANDLE);
	SetConsoleCursorInfo(handle, &curInfo); 
}

void CursorJump(int x, int y){
	COORD pos;
	pos.X = x;
	pos.Y = y; 
	HANDLE handle = GetStdHandle(STD_OUTPUT_HANDLE);
	SetConsoleCursorPosition(handle, pos); 
}

void InitInterface(){
	color(6); 
	for(int i = 0; i < ROW; i++){
		for(int j = 0; j < COL; j++){
			if(j == 0 || j == COL - 1){
				face[i][j] = WALL;
				CursorJump(2 * j, i);
				printf("■");
			}
			else if(i == 0 || i == ROW - 1){
				face[i][j] = WALL; 
				CursorJump(2 * j, i);
				printf("■");
			}
			else{
				face[i][j] = KONG;
			}
		}
	}
	color(7); 
	CursorJump(0, ROW);
	printf("当前得分:%d", grade);
	CursorJump(COL, ROW);
	printf("历史最高得分:%d", max);
}

void color(int c){
	SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), c);
}

void ReadGrade(){
	FILE* pf = fopen("贪吃蛇最高得分记录.txt", "r"); 
	if(pf == NULL) {
		pf = fopen("贪吃蛇最高得分记录.txt", "w");
		fwrite(&max, sizeof(int), 1, pf); 
	}
	fseek(pf, 0, SEEK_SET); 
	fread(&max, sizeof(int), 1, pf); 
	fclose(pf); 
	pf = NULL; 
}

void WriteGrade(){
	FILE* pf = fopen("贪吃蛇最高得分记录.txt", "w");
	if(pf == NULL) {
		printf("保存最高得分记录失败\n");
		exit(0);
	}
	fwrite(&grade, sizeof(int), 1, pf); 
	fclose(pf);
	pf = NULL; 
}

void InitSnake(){
	snake.len = 2; 
	snake.x = COL / 2; 
	snake.y = ROW / 2; 
	body[0].x = COL / 2 - 1;
	body[0].y = ROW / 2;
	body[1].x = COL / 2 - 2;
	body[1].y = ROW / 2;
	face[snake.y][snake.x] = HEAD;
	face[body[0].y][body[0].x] = BODY;
	face[body[1].y][body[1].x] = BODY;
}
//随机生成食物
void RandFood(){
	int i, j;
	do{
		i = rand() % ROW;
		j = rand() % COL;
	} while (face[i][j] != KONG); 
	face[i][j] = FOOD; 
	color(12); 
	CursorJump(2 * j, i);
	printf("●"); 
}
//判断得分与结束
void JudgeFunc(int x, int y)
{
	//若蛇头碰到的是食物则得分
	if(face[snake.y + y][snake.x + x] == FOOD)
	{
		snake.len++; //蛇身加长
		grade += 10; //更新当前得分
		color(7); 
		CursorJump(0, ROW);
		printf("当前得分:%d", grade); 
		RandFood(); //重新随机生成食物
	}
	//若蛇头碰到的是墙或者蛇身则游戏结束
	else if(face[snake.y + y][snake.x + x] == WALL || face[snake.y + y][snake.x + x] == BODY)
	{
		Sleep(1000); //留给玩家反应时间
		system("cls"); 
		color(7); 
		CursorJump(2 * (COL / 3), ROW / 2 - 3);
		if (grade > max)
		{
			printf("恭喜你打破最高记录，最高记录更新为%d", grade);
			WriteGrade();
		}
		else if (grade == max)
		{
			printf("与最高记录持平，加油再创佳绩", grade);
		}
		else
		{
			printf("请继续加油，当前与最高记录相差%d", max - grade);
		}
		CursorJump(2 * (COL / 3), ROW / 2);
		printf("GAME OVER");
		while(1) //询问玩家是否再来一局
		{
			char ch;
			CursorJump(2 * (COL / 3), ROW / 2 + 3);
			printf("再来一局?(y/n):");
			scanf("%c", &ch);
			if(ch == 'y' || ch == 'Y')
			{
				system("cls");
				main();
			}
			else if(ch == 'n' || ch == 'N')
			{
				CursorJump(2 * (COL / 3), ROW / 2 + 5);
				exit(0);
			}
			else
			{
				CursorJump(2 * (COL / 3), ROW / 2 + 5);
				printf("选择错误，请再次选择");
			}
		}
	}
}

void DrawSnake(int flag)
{
	if(flag == 1){
		color(10); 
		CursorJump(2 * snake.x, snake.y);
		printf("■"); 
		for (int i = 0; i < snake.len; i++){
			CursorJump(2 * body[i].x, body[i].y);
			printf("□"); 
		}
	}
	else{
		if(body[snake.len - 1].x != 0){
			CursorJump(2 * body[snake.len - 1].x, body[snake.len - 1].y);
			printf("  ");
		}
	}
}

void MoveSnake(int x, int y){
	DrawSnake(0); 
	face[body[snake.len - 1].y][body[snake.len - 1].x] = KONG; 
	face[snake.y][snake.x] = BODY; 
	for(int i = snake.len - 1; i > 0; i--){
		body[i].x = body[i - 1].x;
		body[i].y = body[i - 1].y;
	}
	body[0].x = snake.x;
	body[0].y = snake.y;
	snake.x = snake.x + x;
	snake.y = snake.y + y;
	DrawSnake(1); 
}

void run(int x, int y){
	int t = 0;
	while(1){
		if(t == 0)
			t = 3000; 
		while(--t){
			if(kbhit() != 0) 
				break;
		}
		if(t == 0) {
			JudgeFunc(x, y); 
			MoveSnake(x, y); 
		}
		else{
			break; 
		}
	}
}

void Game(){
	int n = RIGHT; 
	int tmp = 0; 
	goto first; 
	while(1){
		n = getch(); 
		switch(n){
		case UP:
			case DOWN: 
			if(tmp != LEFT&&tmp != RIGHT){
				n = tmp; 
			}
			break;
		case LEFT:
			case RIGHT: 
			if(tmp != UP&&tmp != DOWN){
				n = tmp; 
			}
		case SPACE:
		case ESC:
		case 'r':
		case 'R':
			break; 
		default:
			n = tmp;
			break;
		}
		first: 
		switch(n){
			case UP: 
			run(0, -1); 
			tmp = UP; 
			break;
			case DOWN:
			run(0, 1); 
			tmp = DOWN; 
			break;
			case LEFT:
			run(-1, 0); 
			tmp = LEFT; 
			break;
			case RIGHT: 
			run(1, 0); 
			tmp = RIGHT; 
			break;
			case SPACE: //暂停
			system("pause>nul"); //暂停后按任意键继续
			break;
			case ESC: //退出
			system("cls"); //清空屏幕
			color(7); 
			CursorJump(COL - 8, ROW / 2);
			printf("  游戏结束  ");
			CursorJump(COL - 8, ROW / 2 + 2);
			exit(0);
		case 'r':
			case 'R': //重新开始
			system("cls"); 
			main(); //重新执行主函数
		}
	}
}

